public class Example4_7 {
 public static void main(String args[]) {
  Battery nanfu=new Battery(100);
  System.out.println("南孚电池的储电量是:"+nanfu.electricityAmount);
  Radio radio =new Radio();
  System.out.println("收音机开始使用南孚电池");
  radio.openRadio(nanfu);
  System.out.println("目前南孚电池的储电量是:"+nanfu.electricityAmount);
}
}

